Fixing the Position of Context Menu for BrowserPlugin (<webview>)

content/browser/frame_host/render_widget_host_view_guest.cc

Index: content/browser/frame_host/render_widget_host_view_guest.cc
diff --git a/content/browser/frame_host/render_widget_host_view_guest.cc b/content/browser/frame_host/render_widget_host_view_guest.cc
index f5a04c4cc6fb1e2c152e847173fabf94ac7f013d..ad7235a0d78d6d476bd006150d8b732ec6d8208d 100644
--- a/content/browser/frame_host/render_widget_host_view_guest.cc
+++ b/content/browser/frame_host/render_widget_host_view_guest.cc
@@ -625,8 +625,21 @@ void RenderWidgetHostViewGuest::OnHandleInputEvent(
     const gfx::Rect& guest_window_rect,
     const blink::WebInputEvent* event) {
   if (blink::WebInputEvent::isMouseEventType(event->type)) {
-    host_->ForwardMouseEvent(
-        *static_cast<const blink::WebMouseEvent*>(event));
+    // The mouse events are subject to whatever CSS transforms
+    // applied on the BrowserPlugin. This causes the reported position of
+    // ContextMenu from the guest renderer become potentially incorrect. As a

[wjmaclean, 2015/08/17 13:05:23]

-> "... renderer to potentially be incorrect."

[Ehsaan, 2015/08/17 14:09:12]

Done.

+    // hack, the position is calculated here and reported to the
+    // BrowserPluginGuest.
+    const blink::WebMouseEvent& mouse_event =
+        static_cast<const blink::WebMouseEvent&>(*event);
+    // A MouseDown on the ButtonRight could suggest a ContextMenu.
+    if (guest_
+        && mouse_event.type == blink::WebInputEvent::MouseDown
+        && mouse_event.button == blink::WebPointerProperties::ButtonRight)      
+      guest_->SetContextMenuPosition(

[wjmaclean, 2015/08/17 13:05:23]

Will the transformation ever be more than just a translation? Will scale and/or
rotation ever be an issue?

[Ehsaan, 2015/08/17 14:09:12]

This translation is based on globalX/Y which is supposed to be untouched, plus
the corner point of the view. This should become the value where the context
menu was supposed to be shown. I am doing this on the browser side to avoid the
CSS transformations. The way it normally work is for the renderer to undo the
transforms is here (I guess):
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...

Which is not done (and should not be I believe) in the case of BrowserPlugin.
This even is supposed to be carried to the guest renderer and changing the
coordinates at the renderer side will break functionality.

+          gfx::Point(mouse_event.globalX - GetViewBounds().x(),
+                     mouse_event.globalY - GetViewBounds().y()));
+    host_->ForwardMouseEvent(mouse_event);
     return;
   }